SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1aa67b316bef9e2b9d67b455aa1dcce65e6d5b08d71a4291a706310c7b40357' 
  AND token = 'stPgYhVFl/xqtGjc+aBYPe3ME+4C9Nlzflzw0qJmjVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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