SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd243388f4b1e4ce3a194ce69b72ea9ab2d0318d6c355aa858f5b2060be1968f8' 
  AND token = 'xub9BLV6zq+pC51L/8Tm6jTK7mQz50oZx1RAV88JMUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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