SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7138d1399e5ffe5ed56932e42766f992c610e53b1f270533457167e1327ffc66' 
  AND token = 'VuV+mPgFo1GlAHeTv3kpe52poQKVYQmZiE0RqxdvoGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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