SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8526a5902050f115e858a876de4f388280fdff82084346f03b89660eeeec619' 
  AND token = 'clW5ZWt57TrG+QDlboEjzFHo/vZJG30UmaDLV79s87o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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