SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f02b1701935957c24814ffd795ddb27e99c43fdde6c9974f1b4227a52a536bb' 
  AND token = 'AqgLF/og2a0wJT/kSqdKAaomo3Ov7EnIn15NbDCplQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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