SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfc8e3dd096b2332b3ac607665c5de000bbd66d2a0d2a9201e9f035241e79f66' 
  AND token = 'LqAIb4JawzR5BIjNmnhMSTAU6XvNW24G9NNH9arZZ+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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