SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9855d7481109185ac70439c506af8ddfad36b0848ee0b613fcf47d5ef0a85819' 
  AND token = 'pKm6ZKCA+9qCgyPmfVWDBEvi9KxHk6tCZLFOBh+XtLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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