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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b5b89f4d5c48b814c300563dd4f71cbce0acc1362cfc0c9eb8fe9fbb78684e1' 
  AND token = 'vJ3wrPDntX0g+xiA/QkcHMPV6EEZqWcEHK15GyEx4Sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}