SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd78e4f122371e01785b1751a5bec2c0f97d7351e60323465b1ac948688bb4ca3' 
  AND token = 'hRXSAVgsM9CETcRIRbrScAiYmuyvEDsy+DW2+n4vZ5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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