SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df5b6d64431573d8071785007f98db418aac6c7ecaa43c72ba9e3175b27f247' 
  AND token = 'vEE+tBoLncTrtEpoGikFkIH7kzqGsPs2aCqLj2o+Ao0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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