SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5998c9c8ecd55fe0e27e99750b4c05a4795efee1cd47d9ebfd7e57d95d6fe73b' 
  AND token = 'TCA+/HZt6Ni66I5LBPNgWg7EvjQ1/OsKAl18Fd5Vk+M=' 
  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"
    }
  }
}