SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e40dfd15fe7405292a638b670f68100e1533987dd6f87911d313b5e919dcfd70' 
  AND token = '7NmlehXXqvlRAftbexEmwDjCN1J9pOHgFiHamWewEKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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