SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e52e5273aaafa1ce3d8651f435ef1835ea3fe5142c71432802f42590885e38a' 
  AND token = 'Ade/sAf2JZ2ZUDPP7BhANguSWqwBGxLpU5isUpfcG3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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