SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f2187a94731a98d6068025bf799d4b23d045baa4e9d4eaaa619b122e6317652' 
  AND token = 'xtptEKqllcXeYairrB5oFucRUTGeIBWvnFLE1E+bYwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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