SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc51e1a7f85d4d6309b7158e8ec866618892d817858385615f7e1f7da85f34e5' 
  AND token = 'WcQIRBOBHq3/IfLOOVET2qAhHdIvbCNN+L/5xIi3wPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}