SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55b4681e211bebde6139ceaaa90dd036f9f52d6bdb29268a8880072d28cdca65' 
  AND token = 'TeDq4AGYyGnro9Jdd2vJEliZwgjLqK7tw15FdiZ1aX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}