SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e947fdfeaab32ad632f15f934b8170b45557e421877cbe5f598d8aa326bfa1aa' 
  AND token = 'JMWO59/CDZ6TwQiY3iouI2iSI5BY8ZZWxQA0GLra6OY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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