SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bb63502525a536447e933822741ef548b765d5ad133ee553551eda535a056aa' 
  AND token = 'UwdVdh7+U2MCt6RSwYNjkhUzJcvyyE28nfFWpD8RQHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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