SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fec5b655cfb41146b21eadba071909f1bdd7db3a219ca7b38aadae298fac949b' 
  AND token = 'J84JeqB32LCRzZMEuP5dHkFVM95dYGi2BfDEmgWjPJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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