SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f43c1ccf73e2c06445f01164c267f169184c6842be759cd9a5cb4bfb227b9d4' 
  AND token = 'DXjjELicxO0EAHKyd43Srk2+KxPixKHQIJsTCNF/5Fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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