SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5560c1b6550989ad4be084f2879380357d39fb30d4c3632c5eb1232646602cf' 
  AND token = 'xGBwxL8auJUigjW7lTKP3sEYAuNqrY8cHKQvhbNA1kc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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