SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108abafc0fdcce995f447b72fdb04d07d56fb08647b9a9cefff1f82e29e55035' 
  AND token = '2SUGM/VdKPLBKNeaJwWNRgEAq4JKrYtFP9Jj+PSXgh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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