SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8db4718cad082638c0f86597d21f92f12b86e2e36e0277be0f4236499dc02012' 
  AND token = 'gIJQUD4B/swEbrub1rYNsMfagSZ2KagzS+OxS5EA4MY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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