SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '481f1a31bf95f0983fbdb01d96db6c1a1fc476d7b7ff4dff3e9707b42e3566da' 
  AND token = 'AB6KHaZBPzJibglcUl+sYWUAAuFBL2c36gSaZRUjBuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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