SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e8ea51f04df78aedb94f12651e5919d1756c0acf50e28a66aff6913bd69bfbd' 
  AND token = 'DjnNMqm6uP9xLjtG/JHPv2qxV3i4F5VWKgkTP4UrVW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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