SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b65d796cd98d26183833314c87dcd8c862be876ca71d1a4b948c1289eff0fc36' 
  AND token = 'z4Ooffyh8FoP9CjrkPfonURZwKWl6CdZwXTLkYU9QOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}