SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e2c1c5e15e9171b58632a1380c95178aa187ae5ecda77bbbd8be3a93b41e999' 
  AND token = 'mH4VPJg4trDAFWuGs5Gs6WY/iixnPJ2cElepJjdvbUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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