SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87019307509c8e5c32ad9093100a563086409feff59f4ed817e65109b18f2ca1' 
  AND token = 'zdrFaiiCVM/EjBu3FIEFfCcC7xxSEWiBQPQsWviOrOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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