SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65f1246a66014bc0419ea8c092456a560402ab3780ac464938d253b7117c86f3' 
  AND token = '16/j5lcfuAWKHEVeRXJIP2z7AbgltLdr6XtnCq+ZDhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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