SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c59fba07bf21ccbc9b11800543b27116e68dd76ee70c30cf922baaaf31c4e2fb' 
  AND token = 'X9BvUxS4EHVkTpVALdHL5oEr7hjYY7yy8mkXZMtnY78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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