SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c5b8baae5065bcfa5d89ccf92faa3b92b41fdbefd3d41243eec57f211a0035ca' 
  AND token = 'M/uvugZ4qdmvV7QXoM3c2j1R5srOlkvvfjfUFW8cvC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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