SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34d687f9374b2fa9132d4ced80168350eebf67ec37deb8039fb13370a684dad5' 
  AND token = 'w08l6QVdV4817nw1TtSECkJlv3JEohjN5adnp4JAPMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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