SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33da04dfe07046be3aeed8856d56475b4d9f7f9652f4032b61057e6cd3c9d965' 
  AND token = 'zvg3nuPDvBqWt5FCYmjsWh1/fIyFPsn8ekKteZJ7PWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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