SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e8ad8135b352c0b5a0d6f0fca302b3f7bf6d649bf047024647f1a11f2b5e84d' 
  AND token = 'hmvXR4UytyhH7PU+I5h6F3AsVXGiZ7uQqhqogHrgbmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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