SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e568c952e29b09333ed459287e14684f4619f751f553f31e253d023da233fd10' 
  AND token = 'BXIuR/980sTx/WHdk/JdQc1E31JrUOyejD3gYTEWIss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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