SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2e73bc2b9414fda6cfedf7f1a81006909fb3c973611ba2172669b68461e4835' 
  AND token = 'TkKeXYjTBqVB+g0B3nJQWihxLIYFvt6mA1+NKtIIy00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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