SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '439e86906d647708fe7e56d749587ab2bc2d3f3463b35e0275a4793b80c47194' 
  AND token = 'D6hScRv1Kub8psgjLcnBUFm2CvIPMLtTOXcJvT6iAb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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