SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80aee750036e546d33ee408efb6abddd4d4616807eb6da1d662344570d890f65' 
  AND token = 'fv4Z7rjoXef99l/Yut6JlMi3LCsxwfme04no3sxWsP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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