SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5671e24c0b8d5a68d0dd636d963f25023d1d92eee556afd24aa261089611b84a' 
  AND token = 'f5DPNwSBoVzueWsa5hrMqfABbpPPPnowKjKEuARnXo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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