SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '252066a073b0a2e4c672ae8341598d5835b98d8b8b6d897fa130fb5c755a2a48' 
  AND token = 'FJkRplWBjJDx9hBb+NByFUT8mYXOqqqJbT84f7vdpIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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