SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dd2debd5c98366050b4d636a7a2a0558fcfa4651a2394b2715479879eb2cafd' 
  AND token = 'x1dDylRA3zKRRjYUf2KFGUcx0Wpl4TO7vGwqbHSmaJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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