SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36f6cf246fe7a2782e55fa5198aa4485546ad5d743361156a1d766a206269821' 
  AND token = 'RiRLb2hUmkwcIlYz/lkmbcWorQ49fNlNfHXppPoM9AI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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