SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e207cfca5e861ba5288c7b57d90334705ad3dc41d68ed852d30d443d14baf3fd' 
  AND token = 'UZlm0Zsz2BFLngWsQRjKsEzyOstzSTMARPP9mpWN6rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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