SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bd0840976dce30d1299ceb063bdffa59ab85ffbfd27a3c3cbca3a9de638e7d4' 
  AND token = 'YTeac2FlvfibXrD+xoxyAp8KNxDuUPnrcHZ7gEjCvlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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