SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a28ce18d5c76b97df6b93a9b2205dea8cff73749d2ff3a38c74caeda294d4b1' 
  AND token = '7UTk9DX0uRDrWiwvWjPcNsfVEBbSs2Z+oI8JlkSedjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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