SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6deaa980b15ecce787e824903bcd5eced5bfd0950077ffd6c5612f1559cced6b' 
  AND token = 'KebxNisgzZAgG8Qsoo6wDJRRXvhzPrVPO0e8TmJSiX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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