SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18f156dd147ae3c08c762b2453599ce5fcfd5b144f6c250d065cd0d8bc94df7a' 
  AND token = 'mdKJu9QCVowalEq5We4eFyyfqHxMQZwjPUbYmzKKUX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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