SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '285727457549ec737a5c48545eeb5f802b1737e1abd4edf1c81d4c1d0318b98e' 
  AND token = 'guz8BbO9DT6lMZYadTofAngg38+wcR0I6kvXGrVSU9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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