SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f816f53539fe0bfd1527369a8d6140146e4ac8ece2668eccb552d7379d9fc9fc' 
  AND token = 'fWpIOergfbW2vN7N3eO3vD2xWunXzgL2n6NsunOCkaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}