SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fed17ec0b4e39bbe351fdca5e6f19ad0bd90c2780c145ab57c71a3412cbbf927' 
  AND token = '+UGnxS876VMLSBf2sKTYUrkgLkOuhotGCjPOHG1BpWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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