SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b755a8f17943dbeef98e672b25bd51f9d2407fa77c35623e4ed1d9288d67319c' 
  AND token = 'mTn+OwD058Bu/hWoLC95YzVDCVlWO4O/lmpUJVj46Kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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