SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fb7d4b5627d2c4ffe53afbeb0c4bb382a01a0163af1592f7318cd24b53f20164' 
  AND token = 'd0IikHRsF3lc8UWtnljN+uPjaCOa+it1GF2SsP4NfMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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