SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '937b44865f09c5d2b4e959d5b0618709ed182b18146f25fcf63597c4f6c5299e' 
  AND token = 'WQ8vPc6xHQ0oozDQShTK5P/9znR7Hy1Oz/MYSeHfhsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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