SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '272ef537cf430049babd3f17b872f4b98c6abee82ac4c1a1dccea176e590e52f' 
  AND token = 'U0vAzFGQ+dRovMjPZuMJI2nIDY6SlQJAPLgxMVIzx7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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