SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b252b15173a9d75a08d0532cc102dddfff8349f6a80b2d83af5d9960c6fc202' 
  AND token = 'JlARQiWhr6z/gFjxsBBwXDMUiNGp7nZJ9xRc7aAsd1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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