SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd98f53e61123d3e9e9c807896f9dfa41acebb51a91988ae0aa745cef4bc2f5c5' 
  AND token = 'CSywI9/rZlbvyAtHLG33xdwCnEBC2wfkZEa5Mv+nXnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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