SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d4ed2356c557754a0b6a08336006e873a348022ede72e09c4e7752eaf026442' 
  AND token = 'lx3An9UjxuhGBEUQu9AyBS0vhs7z0BlPk6XKGGqWMew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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