SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd12faed41f54a45d55279222ff5726f6192136e5f23cb5116d21d3ca1e8d7818' 
  AND token = '70KUVu3Wd1Gz33kgLwEzCWDh+pU/CSlBQmlnSg8ul/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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