SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b69b1af1b37d333fa8b5813560938281dfcb6217fdfa79d8d80f8998a4bc38d' 
  AND token = 'hgaPNB2vh/WXQcs3Ae5thdYsFH4ePnvAddBZ7WAjDgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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