SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35b08808bac91f1e7fc185313da5df83243752785a85bcd269dae30af89ab884' 
  AND token = 'EQkjOvwhJksOHInNyV9cexW2/0c6FQWu2ly2M+WqdpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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