SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c8ca2799ee47071e3ecb16ebb7a9e44913cceecbc385ce04f52b263cb1676c8' 
  AND token = 'du6nbPS56wjChNzK3gtc3r4Nkc2jKVfNjaCzWlusm3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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