SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0ab498e36241856d378a2f392ba4cabed0884ab6b73426c952b29a016685df' 
  AND token = 'MJkiPmBm5HwXDNSzaybQOs1+UKgQEL5FmGq4piETVsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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