SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd6d0fe344f1bb2156c0541aa41897ef93efb276c9ba2d0da296e83299a8c91e' 
  AND token = 'PHUNOj28qpMS3TpioVcrpQHdN7ed8Geh/EPljgwCHkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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