SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13de1e58fb3734032a10126fd6187ff75b3b185b457dda08e063ab42569ba553' 
  AND token = '7ZKcFaOOysM8frM0tsxXrkwfbIWaolIEYq1m+zcxKgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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