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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fbfee21bae3793beb7e7cb8bd02dfcd1d4d1d277f6379ebc7e9faf9e2a4f99c' 
  AND token = 'CzgOwGuU73ocajqU7y4azjDpfZRg85iar9uL+CQtomU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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