SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89bf7bf3a9392057ae5791caacaf368be7de49845fe9e2a7dc8a965b1eed136f' 
  AND token = '5Qbh1oQKvVeZwgszmLO7PW8FTcqZCeeDlS57cHHNXU8=' 
  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"
    }
  }
}