SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419de64d823812fa52d5a3dfcedea65181a9b7c0a8e7d65a1d9da392fab119db' 
  AND token = 'ODigtwyqgd/n0Y0VpepZgW2LjJPGIrl7qvMTEPN77+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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