SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac6a89d89086da907546c3f7d0771a54300079baeb20245fa1f15ac556902c0' 
  AND token = 'PBVZuCB1nsJWb+WSuwHCyLa8fbNqevlrz96NER0VkuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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