SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c69885fda7c563a13c51cade97fcbe3003501ca6f3384ae4f8c47315f20493fe' 
  AND token = 'hWDmMNvyfYvOuZ+bkJ9nn4yFqdtOpy8HPk5qbGiKheA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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